Are you getting errors like "Unhandled loop event exception" messages in your console with nothing useful after it? Make sure you have [http://wiki.eclipse.org/Graphical_Eclipse_FAQs#I_get_an_unhandled_event_loop_exception_in_my_console._What_gives.3F -consoleLog] as a '''Program Argument''' in your launch configuration. You may also want to take a look at these [[Core Tools|runtime tools]].

Are you getting errors like "Unhandled loop event exception" messages in your console with nothing useful after it? Make sure you have [http://wiki.eclipse.org/Graphical_Eclipse_FAQs#I_get_an_unhandled_event_loop_exception_in_my_console._What_gives.3F -consoleLog] as a '''Program Argument''' in your launch configuration. You may also want to take a look at these [[Core Tools|runtime tools]].

−

===I'm using third party jar files and my plug-in is not working...===

+

===I'm using third party jar files and my plug-in is not working===

Did you add those jars to your project's '''Java Build Path'''? Do not use that project property page when developing plug-ins. You have two options.

Did you add those jars to your project's '''Java Build Path'''? Do not use that project property page when developing plug-ins. You have two options.

Line 41:

Line 41:

# Export any packages that you need to using the PDE Editor>Runtime tab

# Export any packages that you need to using the PDE Editor>Runtime tab

# Save

# Save

+

+

'''Common mistakes for option 2'''

+

+

One common mistake is to forget to add the '.' to the classpath after adding your library.

+

If you fail to do this, your plug-in will crash with a message like this:

+

java.lang.ClassNotFoundException: lib.foo.Bar

+

at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:513)

+

at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:429)

+

at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:417)

+

at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)

+

at java.lang.ClassLoader.loadClass(Unknown Source)

+

...

+

+

Example of META-INF/MANIFEST.MF:

+

// lib.foo MANIFEST.MF

+

Manifest-Version: 1.0

+

Bundle-ManifestVersion: 2

+

Bundle-Name: Foo

+

Bundle-SymbolicName: lib.foo;singleton:=true

+

Bundle-Version: 1.0.0.qualifier

+

Bundle-Activator: lib.foo.Activator

+

Bundle-ActivationPolicy: lazy

+

Bundle-RequiredExecutionEnvironment: JavaSE-1.6

+

Import-Package: org.osgi.framework;version="1.6.0"

+

Export-Package: lib.foo

+

Bundle-ClassPath: lib/someRandomDep.jar <--- WRONG

+

Bundle-ClassPath: .,lib/someRandomDep.jar <--- CORRECT

+

+

Also check whether your build.properties file now lists the '.' and the 'lib'-directory (or whatever you named it) in 'bin.includes':

+

bin.includes = META-INF/,\

+

lib/,\

+

.

+

+

Check out {{bug|108781}}.

Check out {{bug|108781}}.

Line 92:

Line 126:

===A plug-in in my 'Eclipse Application' launch configuration is listed as being "out of sync", what should I do?===

===A plug-in in my 'Eclipse Application' launch configuration is listed as being "out of sync", what should I do?===

One known workaround to this problem is to remove your workspace's <code>.metadata/org.eclipse.pde.core</code> folder. Cleaning and reloading the target platform does not appear to fix this problem.

One known workaround to this problem is to remove your workspace's <code>.metadata/org.eclipse.pde.core</code> folder. Cleaning and reloading the target platform does not appear to fix this problem.

+

+

===How do I include native libraries in my bundle?===

+

When you want to use native libraries within your bundle using custom libraries, you can either tell the user to set the appropriate system environment path or include those libraries in the plug-in.

'''Caution:''' If you get an <tt>UnsatisfiedLinkError</tt> when you load a library which depends on a library which hasn't been loaded yet. To overcome this automatically, you can iterate over a list of the required libraries, and throw all out which could be loaded, until the list is empty. Like this, you can compute the correct ordering for loading your libraries.

+

+

<source lang="java">

+

/**

+

* Iterate through the list of libraries and remove all libraries from the list

+

* that could be loaded. Repeat this step until all libraries are loaded.

+

* The Reason: You can only load a library, if all dependent libraries have

+

* already been loaded. So you need to know the correct ordering from the

+

* leafs to the root. Load the leafs first!

+

*/

+

ArrayList<String> toRemove;

+

int i = 10; //cancel after 10 iterations. You probably forgot to mention a library to load.

+

while (!list.isEmpty() && (i > 0)) {

+

toRemove = new ArrayList<String>();

+

int j = 0;

+

while (j < list.size() - 1) {

+

try {

+

System.loadLibrary(list.get(j));

+

toRemove.add(list.get(j));

+

System.out.println("loaded library " + j + ": " + list.get(j));

+

} catch (Throwable e) {

+

// System.out.println(e.getMessage());

+

// System.out.println("error loading lib: " + list.get(j));

+

}

+

j++;

+

}

+

for (String lib : toRemove) {

+

//System.out.println("removing lib : " + lib);

+

list.remove(lib);

+

}

+

i--;

+

}

+

</source>

+

+

Please note that for debugging, <tt>e.getMessage()</tt> may give you more information for debugging. It can assist you if you mistyped some of the library names for instance.

+

+

You should not use this code for production but to compute the correct ordering of your libraries!

==User Interface==

==User Interface==

Line 205:

Line 303:

if (provider != null) {

if (provider != null) {

provider.setSelection(...);

provider.setSelection(...);

+

}

+

</source>

+

+

===How do I get the selection of an editor or view?===

+

You can retrieve the selection from the ISelectionService or get it directly from the selection provider of the part from its site.

// this can be null if the workbench part hasn't set one, better safe than sorry

+

if (provider != null) {

+

ISelection selection = provider.getSelection();

+

/* ... */

}

}

</source>

</source>

Line 215:

Line 332:

}

}

</source>

</source>

+

+

===How do I make a New / Import / Export Wizard appear in the context menu of the Project Explorer?===

+

Add an extension to the extension point [http://help.eclipse.org/helios/index.jsp?topic=/org.eclipse.platform.doc.isv/reference/extension-points/org_eclipse_ui_navigator_navigatorContent.html org.eclipse.ui.navigator.navigatorContent] with a commonWizard element that points to the ID of your wizard.

==Editors==

==Editors==

Line 392:

Line 512:

==Release==

==Release==

−

===How do I make a p2 repository===

+

===How do I make a p2 repository?===

This is not the only way to create a repository, and it may not be the best way, but it worked for me. YMMV.

This is not the only way to create a repository, and it may not be the best way, but it worked for me. YMMV.

Line 436:

Line 556:

</project>

</project>

</source>

</source>

+

+

===How do I add files to the root of the installation directory?===

+

You can include [http://help.eclipse.org/indigo/index.jsp?topic=/org.eclipse.pde.doc.user/tasks/pde_rootfiles.htm] with your build.

+

+

PDE/Build will take the feature root files and generate p2 artifacts with touchpoint stuff to do the right thing at install time.

[[Category:FAQ]]

[[Category:FAQ]]

[[Category:RCP]]

[[Category:RCP]]

Revision as of 12:50, 30 November 2012

This page is a collection of FAQs that is intended to help a developer write Eclipse plug-ins.

This FAQ is intended to be complimentary to the Official Eclipse FAQ and RCP FAQ wiki pages. If you cannot find your question here, you should try checking those other two pages.

General Development

How do I find a class from Eclipse?

I see these $NON-NLS-1$ tags all over the place when I'm browsing Eclipse's source code? What do they mean?

They are meant to mark a string literal as not needing to be externalized (as
in, translated / localized). You will often see something like...

if(string.equals("")){//$NON-NLS-1$// do stuff}

...this would be a scenario where a string wouldn't need to be localized
because it is a string for the code to "manipulate", per se, over it being
part of a message to the user at the UI level.

I need help debugging my plug-in...

Are you getting errors like "Unhandled loop event exception" messages in your console with nothing useful after it? Make sure you have -consoleLog as a Program Argument in your launch configuration. You may also want to take a look at these runtime tools.

I'm using third party jar files and my plug-in is not working

Did you add those jars to your project's Java Build Path? Do not use that project property page when developing plug-ins. You have two options.

Option 1: turn the jars into plug-ins
Use New > Project > Plug-in Development > Plug-in from existing JAR archive. That will turn one or more jar files into a single jar plug-in. For something like log4j you can then set up Buddy-Classloading, etc.

Prior to 3.2.1, you had to make modifications to the build.properties file. See bug 146042 (RCP export has problems with required plug-ins).

Option 2: include the jars in a plug-in

Use Import>File System to import the jar files into your plug-in project, say in the <project>/lib directory.

Use "Add..." to add the jars to the classpath section of the PDE Editor>Runtime tab.

Use "New..." to add "." library back (with no quotes, of course). Some versions of eclipse automatically do this for you.

Make sure your binary build exports the new jar files on the PDE Editor>Build tab.

Save

On the project, use the popup menu>PDE Tools>Update Classpath to correctly add the jars to the eclipse project classpath.

Export any packages that you need to using the PDE Editor>Runtime tab

Save

Common mistakes for option 2

One common mistake is to forget to add the '.' to the classpath after adding your library.
If you fail to do this, your plug-in will crash with a message like this:

java.lang.ClassNotFoundException: lib.foo.Bar
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:513)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:429)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:417)
at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
at java.lang.ClassLoader.loadClass(Unknown Source)
...

How do I read from a file that I've included in my bundle/plug-in?

The FileLocator class should be able to do most of the things that you want. It can open up a java.io.InputStream as well as provide a java.io.File. You should keep in mind that the java.io.File approach is not going to work if your bundle is packaged as a jar file. To get a reference to your bundle's Bundle instance, you can use Platform's getBundle(String) method. Alternatively, if your bundle's activator subclasses Plugin or AbstractUIPlugin, then you can just call getBundle() from it directly. If your activator simply implements the BundleActivator interface, then from your implementation of the start(BundleContext) method, you can just call getBundle() on the passed in BundleContext to store the Bundle instance in a field for retrieval later. You can also query for Bundle instances from the PackageAdmin service.

Where do I find the javadoc for the Eclipse API locally? I don't always want to load stuff up in a browser.

You will already have the javadocs for the Eclipse Platform if you installed the Eclipse SDK. The HTML files are stored in the org.eclipse.platform.doc.isv jar file located in your eclipse/plugins folder. Likewise, you can find JDT APIs in their org.eclipse.jdt.doc.isv jar file and so on.

A plug-in in my 'Eclipse Application' launch configuration is listed as being "out of sync", what should I do?

One known workaround to this problem is to remove your workspace's .metadata/org.eclipse.pde.core folder. Cleaning and reloading the target platform does not appear to fix this problem.

How do I include native libraries in my bundle?

When you want to use native libraries within your bundle using custom libraries, you can either tell the user to set the appropriate system environment path or include those libraries in the plug-in.

Caution: If you get an UnsatisfiedLinkError when you load a library which depends on a library which hasn't been loaded yet. To overcome this automatically, you can iterate over a list of the required libraries, and throw all out which could be loaded, until the list is empty. Like this, you can compute the correct ordering for loading your libraries.

/**
* Iterate through the list of libraries and remove all libraries from the list
* that could be loaded. Repeat this step until all libraries are loaded.
* The Reason: You can only load a library, if all dependent libraries have
* already been loaded. So you need to know the correct ordering from the
* leafs to the root. Load the leafs first!
*/
ArrayList<String> toRemove;int i =10;//cancel after 10 iterations. You probably forgot to mention a library to load.while(!list.isEmpty()&&(i >0)){
toRemove =new ArrayList<String>();int j =0;while(j < list.size()-1){try{System.loadLibrary(list.get(j));
toRemove.add(list.get(j));System.out.println("loaded library "+ j +": "+ list.get(j));}catch(Throwable e){// System.out.println(e.getMessage());// System.out.println("error loading lib: " + list.get(j));}
j++;}for(String lib : toRemove){//System.out.println("removing lib : " + lib);
list.remove(lib);}
i--;}

Please note that for debugging, e.getMessage() may give you more information for debugging. It can assist you if you mistyped some of the library names for instance.

You should not use this code for production but to compute the correct ordering of your libraries!

User Interface

There's a view / editor that I want to model. How do I find out what its source looks like and how it was designed?

Views and editors generally extend ViewPart and EditorPart respectively. Placing a breakpoint in its constructor when you show the view or editor or invoking the "Plug-in Spy" with the Alt+Shift+F1 keybinding will tell you what the name of that class is. From there, you can inspect the class's code to see how it works. In the case of the user interface elements, you should look at its implementation of the createPartControl(Composite) method.

If you cannot get "Plug-in Spy" to run, you may not have PDE installed.

There's a preference / property page that I want to model. How do I find out what its source looks like and how it was designed?

Put a breakpoint in the constructors of the PreferencePage / PropertyPage class. Open the preferences / properties dialog, and then select the page you are interested about. Now you can identify which class is constructing that page based on the stack trace.

You can also invoke the "Plug-in Spy" with the Alt+Shift+F1 keybinding to retrieve information about the page that your mouse is currently hovering over. If you cannot get "Plug-in Spy" to run, you may not have PDE installed.

There's a window / dialog / popup that I want to model. How do I find out what its source looks like and how it was designed?

There are two usual suspects, an SWT Shell or a JFace Window. Generally, most developers subclass's JFace's Dialog class (which is a subclass of Window) for their dialog needs. So you should first try and put a breakpoint in Window's open() method and see if the window you're trying to model stops at that breakpoint when it has been opened (shown). If not, try Shell's open() or setVisible(boolean) methods.

You can also invoke the "Plug-in Spy" with the Alt+Shift+F1 keybinding to retrieve information about the window that your mouse is currently hovering over. If you cannot get "Plug-in Spy" to run, you may not have PDE installed.

There's a wizard page that I want to model. How do I find out what its source looks like and how it was designed?

Wizard pages usually extend the WizardPage class. Putting a breakpoint in its constructor will help you identify the class that is creating that page.

You can also invoke the "Plug-in Spy" with the Alt+Shift+F1 keybinding to retrieve information about the wizard that your mouse is currently hovering over. If you cannot get "Plug-in Spy" to run, you may not have PDE installed.

How do I get the perspective bar to show on the top right corner?

How do I warn the user that a workbench part that is not currently visible has changed?

From your WorkbenchPart subclass, you can use the code below. Please note that the code below currently only works on views. For notification support in editors, please see bug 86221.

IWorkbenchSiteProgressService service =(IWorkbenchSiteProgressService) part.getSite().getService(IWorkbenchSiteProgressService.class);// notify the user by turning the workbench part's title bold
service.warnOfContentChange();

How can I make use of the workbench's browser capabilities?

To leverage the workbench's browser capabilities, you will have to interact with the IWorkbenchBrowserSupport class. The code below will show you how to retrieve an implementation of this interface and open a website with the external browser:

How do I set the selection of an editor or view?

You can retrieve the selection provider from a workbench part from its site.

IWorkbenchPartSite site = workbenchPart.getSite();
ISelectionProvider provider = site.getSelectionProvider();// this can be null if the workbench part hasn't set one, better safe than sorryif(provider !=null){
provider.setSelection(...);}

How do I get the selection of an editor or view?

You can retrieve the selection from the ISelectionService or get it directly from the selection provider of the part from its site.

Note that IFiles are meant to represent files within the workspace and will not work if the file that has been opened is not contained within the workspace. Instead, a FileStoreEditorInput is usually passed into the editor when the editor is opening a file outside the workspace.

How can I make my editor respond to a user opening a marker?

When a marker has been opened, the Eclipse Platform tries to help the user out via the IGotoMarker interface. Your editor should either implement the interface or respond to this class by returning an implementation via the getAdapter(Class) method.

IGotoMarker's gotoMarker(IMarker) method will be called accordingly on the corresponding interface implementation and it is in that method implementation that you can react to a user opening a marker.

Why does the workbench keep opening a new editor every time I open a marker?

Are you using a custom IEditorInput implementation for your editor? You should override Object's equals(Object) method to return true if your custom implementation is equal to another IEditorInput.

Clients implementing this editor input interface should override Object.equals(Object) to answer true for two inputs that are the same. The IWorbenchPage.openEditor APIs are dependent on this to find an editor with the same input.